Improvement in valve-gear for direct-acting steam-engines



UNITED STATES PATENT OFFICE.

W'ILLIAM HQGUILJD AND WILLIAM F. GARRISON, 0F VVILLIAMSBURG, N..Y.

IMPROVEMENT lN VALVE-GEAR FOR DIRECT-ACTING STEAM-ENGINES.

Specitication forming part of Letters .Patent No. 5 1,4511, dated December l2, 1865,

To all whom, it may concern:

and WILLIAM F. GARRIsoN, both of Williamsburg, in the county ot' Kings and State of New York, have invented a new and useful Improvement in the Valve-Gear ot'Direct-Action Steam- Engines; and we do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part ot' this specilication, in which- Figure l is a central longitudinal vertical section of the cylinder, valves, and valve-gear of a direct-action steam-pump illustrating our invention. Fig. 2 is a similar section, exhibiting the valvein a different position. Fig. 3 is a view ot' that side of the cylinder on which the external portion of the valve-gear is situated.

Similar letters of reference indicate corresponding parts in the several figures.

This invention relates to the employment, in direct action steam-engines for working steam -pumps and other purposes, ot1 steampistons, acted upon by steam for the purpose of completing the stroke of the valves commenced by mechanism connected with the main piston-rod; and it consists in a novel construction of such pistons and novel arrangement of passages therein and between the cylinder in which they work and the valve-chest, and in a novel arrangement of mechanism, in connection with the said piston and the valve, whereby, we believe, the desired operation is effected in a more certain and effective manner. K

To enable others skilled in the art to mak and use our invention, we will proceed to describe it with reference to the drawings.

A is the steam-cylinder, on which is a valvechest, B, with which the steam-pipe is connected, and which contains the slide-valve C, the movement of which effects the induction and eduction of the steam to and from the cylinder through the three ports a, a', and b in the valve-seat, the ports a a communicating with opposite ends of the cylinder, and the intermediate one, b, with the exhaust-pipe c. The slide-valve has in its face two cavities, e e', so arranged that when the valve is at its central position (shown in Fig. l) the said cavities will each cover one of the ports a a', the portion of the seat between the said port a or g a and the port b, and the portion 17,01' t", of the Be it known that we, WILLIAM H. GUILD seat beyond the port a or a', the latter portion ot' the seat being in a direction lengthwise of the valve only of a width about equal to that ofthe ports a a', and thebottom ot' the valvechest being recessed, as shown at r r in Figs. land 2, beyond the said portionst' t" of the seat, that the steam may pass under one or other end of the valve and enter the port a or a when the valve is moved from its central position, the other port a or a heilig then in communication, through its respect-ive cavity, e' or e, with the central or exhaust port-,11. The slide-valve C thus constructed has in its back a mortise, d, for the reception ot' the kend ot' one arm, I, of a rock-shaft, E, which works in bearings in the sides of the steam-chest, and one end of which projects through a stuft'- ing-box, and has loosely fitted on it a lever, F, which is connected by a rod, G, with an arm, H, which projects horizontally I'rom the main piston-rod J.

In order to prevent the piston-rod J from turning, it is furnished with a guide-arm, K, which works on' a straight fixed guide, L.

The valve-arm l is fast on the rock-shaft E, and another arm,I/, also fast on the said rockshaft, passes through a slot, ,in the top ot' the steam-chest, and into a cylinder, M, above the valve-chest and parallel with the main cylinder, the said arm entering a niortise, f, in the connecting-stem g of two pistons,N N', which are fitted to work steam-tight in the said cylinder M. These pistons are hollow and open .at their outer ends, and each has an exhaustp ort, m or m', through one side, ranging with one of two corresponding ports, n a', in the cylinder. These ports u u are at a distance apart as much greater than the distance hetween m m as the width of the latter ports; and the said ports n a communicate, by passages p p (shown dotted in Figs. l and 2) made in the side wall of the steam-chest, with the exhaust-pipe c of the main cylinder A.

In the bottom ot' the cylinder M there are two ports, q q', which communicate with the valve-chest B, the said ports being at such distance apart that when the valve C and pistons N Nl are at the center of their stroke, as shown in Fig. 1, the said ports are only just covered by the said pistons.

On the rock-shaft E there are, outside ofthe cylinder, two toes,s s', and on the lever F there are two projections, t t, which, by the movement of the lever F, are made to act against the said toes to produce a movement of the rock-shaft E, valve O, and pistons N N as the main piston arrives near the end of its stroke, such movement ofthe Valve and pistons N N bringing them to-a position from which the action of the steam on one of the said pistons Will complete the movement of the valve to admit steam to the main cylinder to produce the stroke of the main piston in the opposite direction.

'Io explain the opera-tion ot' our invention, we will rst suppose the piston to be moving to the left with reference to Figs. l and 2, and to have nearly completed its stroke in that direction, as represented in Fig. l. Just before the piston arrives inthe position indica-ted in the latter figure, the lever F actuated by the arm H of the piston-rod and the rod G, brings its projection tinto contact with the toe s on the rock-shaft E, and as the movement continues to that position it produces such a movement of thesaid rock-shattthat the arm I brings the valve C to a central position, in which it 'shuts oft' steam from both '1' ort'saa,and brings the pistons NN to such position as to slightly open the port q and to commence the opening otl the port m to the port n', as represented. 'Steam then enters the cylinder M from the valve-chest B, and, acting upon the piston N, moves the two pistons rapidly to the right, and these pistons, by means of the rock-shaft and its arms I I', move the valve C to the left far enough for the latter to open the port a to the steam, as shown in Fig. 2, and steam, then entering the main cylinder A at the left-hand end, produces the movement .of the main piston to the right. During the first part ofthe last-mentioned movement ot' the pistons N N' the steam which has been contained between the piston N and the right-hand end of the cylinder M escapes through the ports un. As the main piston arrives near the end ot' its stroke in a right-hand direction the vprojection t on the lever F acts upon the toe s of the rock-shaft in the same manner .in which t previously acted on s, as hereinbefore described, but in an opposite direction, and so brings the valve C to its central position and the pistons N N to such position that N commences to open the port q to thesteam from the valvechest, which ,entering the cylinder M, produces the movement. of the pistons N N to the left and the valve C to the right, and so admits steam through the port a', to again produce the movement of themain pistonto theleft. These alternating operations are repeated as the piston approaches alternately one and the other end of its stroke.

It should be remembered that in order that the ports q and g may be slightlyopened when the valve() arrives at its central position,closing both ports a (d, the arm I of the rock-shaft should have a slight amount of play within the lnortise d in a direction lengthwise ofthe cylinders A and B.

That We claim as our invention, and desire to secure by Letters Patent, is-

1. The cylinder M, with ports q q and n n communicatin with the main valve-chest and exhaust-pipe, and its two contained pistons, N N', having ports m m', and connected with Vthe valve C by means of the two arms I I ol' herein described.

WM. H. GUILD. W. F. GARRISON. Witnesses:

J. W. CooMBs, A. LE CLERC. 

